1. Technical Field
The present invention relates to a method of manufacturing a variable wavelength interference filter that selects and emits a light a desired objective wavelength from incident light.
2. Related Art
A variable wavelength interference filter is known in which high reflection mirrors are oppositely disposed on the opposing surfaces of a pair of substrates, respectively. In such a variable wavelength interference filter, by reflecting the light between a pair of mirrors, causing only the light of a specific wavelength to be transmitted therethrough, and removing the light of other wavelengths by the interference, only the light of a specific wavelength is caused to be transmitted from the incident light. At this time, in order to cause only the light of a desired wavelength to be transmitted by changing the distance (gap) between the mirrors, high gap accuracy is required in the variable wavelength interference filter. In order to improve the gap accuracy, it is important to secure a uniform joining strength in the opposing substrates surfaces.
Thus, various joining methods are suggested such as a method of applying an adhesive to all joining surface regions, a joining method of interposing a spacer, and a joining method of using a siloxane combination (for example, see JP-A-2001-281443, JP-A-2003-195031, JP-A-2006-350124, and JP-A-2009-134027).
However, in the case of using the joining methods described in the above patent documents, since air is gathered in a gap between the opposing substrates upon gluing the opposing substrates and an internal pressure increases, there is a problem in that the gap between the mirrors cannot be accurately controlled. Furthermore, since a space, where the gap is formed, is sealed, the internal pressure increases due to a change in atmospheric pressure in some cases, and also in this case, the gap cannot be accurately controlled.